Sideband noise mitigation in a co-located network involving CDMA2000 and WCDMA system

摘要

The installation of base station antennas within close frequency range in a co-located scenario constitutes a major interference for radio spectrum engineers. In a co-located setting involving a downlink frequency of CDMA2000 (1960 -1990MHz) and an uplink frequency of WCDMA (1920-1980MHz) as used in the telecommunication industry in Nigeria, the base station receiver is required to receive low amplitude desired signals in the presence of strong transmitting power signals resulting to sideband noise interference. The paper identifies the major mechanism of the sideband noise and proposes the application of a Butterworth Band Pass Filter (BBPF) as a mitigation technique. The technique was developed through the applications of empirical and mathematical analysis conducted in two different scenarios to evaluate the levels of the interference signals on the WCDMA receiver from CDMA2000 transmitter. The first scenario involved a standalone un-collocated WCDMA network while the second scenario involved a co-located network (CDMA2000 and WCDMA). A 52dB required attenuation specification was obtained for the BBPF design.